Known carriers include those coated with a homopolymer comprising fluorinated acrylate or fluorinated methacrylate (Japanese Unexamined Patent Publication No. 53-97,435). However, the polymer forms a coating low in durability, adhesion to the core material, strength, etc.
Also known are carriers coated with a composition comprising a polymer having crosslinkable functional groups and a crosslinking agent (Japanese Unexamined Patent Publication No.60-59,369). However, the composition tends to insufficiently crosslink depending on the crosslinking conditions, forming a coating of low durability. Functional groups in the polymer such as organic acid residues, hydroxyl, epoxy, imino, etc. are hydrophilic and result in lower or unstable electrostatic charge capacity under humid conditions.